This invention relates generally to identification of individuals and more particularly relates to a method of identifying individuals based on biometrics and potential false matches.
Computer security is fast becoming an important issue. With the proliferation of computers and computer networks into all aspects of business and daily lifexe2x80x94financial, medical, education, government, and communicationsxe2x80x94the concern over secure file access is growing. A common method of providing security is using passwords. Password protection and/or combination type locks are employed for computer network security, automatic teller machines, telephone banking, calling cards, telephone answering services, houses, and safes. These systems generally require the knowledge of an entry code that has been selected by a user or has been preset.
Preset codes are often forgotten, as users have no reliable method of remembering them. Writing down the codes and storing them in close proximity to the access control device (i.e. the combination lock) results in a secure access control system with a very insecure code. Alternatively, the nuisance of trying several code variations renders the access control system more of a problem than a solution.
Password systems are known to suffer from other disadvantages. Usually, a user specifies a password. Most users, being unsophisticated users of security systems, choose passwords that are relatively insecure. As such, many password systems are easily accessed through a simple trial and error process.
A security access system that provides substantially secure access and does not require a password or access code is a biometric identification system. A biometric identification system accepts unique biometric information from a user and identifies the user by matching the information against information belonging to registered users of the system. One such biometric identification system is a fingerprint recognition system.
In a fingerprint input transducer or sensor, the finger under investigation is usually pressed against a flat surface, such as a side of a glass plate; the ridge and valley pattern of the finger tip is sensed by a sensing means such as an interrogating light beam.
Various optical devices are known which employ prisms upon which a finger whose print is to be identified is placed. The prism has a first surface upon which a finger is placed, a second surface disposed at an acute angle to the first surface through which the fingerprint is viewed and a third illumination surface through which light is directed into the prism. In some cases, the illumination surface is at an acute angle to the first surface, as seen for example, in U.S. Pat. Nos. 5,187,482 and 5,187,748. In other cases, the illumination surface is parallel to the first surface, as seen for example, in U.S. Pat. Nos. 5,109,427 and 5,233,404. Fingerprint identification devices of this nature are generally used to control the building-access or information-access of individuals to buildings, rooms, and devices such as computer terminals.
U.S. Pat. No. 4,353,056 in the name of Tsikos issued Oct. 5, 1982, discloses an alternative kind of fingerprint sensor that uses a capacitive sensing approach. The described sensor has a two dimensional, row and column, array of capacitors, each comprising a pair of spaced electrodes, carried in a sensing member and covered by an insulating film. The sensors rely upon deformation to the sensing member caused by a finger being placed thereon so as to vary locally the spacing between capacitor electrodes, according to the ridge/trough pattern of the fingerprint, and hence, the capacitance of the capacitors. In one arrangement, the capacitors of each column are connected in series with the columns of capacitors connected in parallel and a voltage is applied across the columns. In another arrangement, a voltage is applied to each individual capacitor in the array. Sensing in the respective two arrangements is accomplished by detecting the change of voltage distribution in the series connected capacitors or by measuring the voltage values of the individual capacitances resulting from local deformation. To achieve this, an individual connection is required from the detection circuit to each capacitor.
Before the advent of computers and imaging devices, research was conducted into fingerprint characterisation and identification. Today, much of the research focus in biometrics has been directed toward improving the input transducer and the quality of the biometric input data. A second important issue to be addressed is the identification process itself and more particularly, the registration process.
A common method of registering users for a biometric identification system is to capture biometric input information, characterise it, and store it as a template. Unfortunately, such a method is limited to data relating to a single user and is prone to false acceptance when two or more users have similar extractable biometric features. This results in significant reduction in security or, conversely, when security is maintained, in significant inconvenience to the users.
It is an object of this invention to provide a means of identifying an individual that is based on data from a user to be identified and data from other users.
It is an object of the invention to provide a method of forming a biometric template providing a second verification method for biometric data without requiring provision of a second biometric information sample to be useful.
In accordance with the invention there is provided a method of identifying an individual presenting a biometric information source to a system. The method comprises the steps of:
receiving a biometric information sample from a biometric information source of the individual;
characterising the biometric information sample;
comparing the characterised biometric information sample against some of a plurality of stored templates to determine a registration profile comprising indicators of a plurality of templates that match the characterised biometric information sample within predetermined limits;
comparing the registration profile against at least a stored registration profile to determine an identification associated with a registration profile similar to the determined registration profile; and,
identifying the individual when the associated registration profile is similar with the determined registration profile within a first predetermined limit.
In accordance with the invention there is provided a method of storing information for use in identifying an individual presenting biometric information comprising the steps of:
receiving biometric information from the individual;
comparing the biometric information to stored templates to determine registration results associated with each of the stored templates, the templates stored within a database of templates; and,
based on the registration results, storing a registration profile including indicators of a plurality of templates stored within the database.
In accordance with the invention there is provided a method of identifying an individual comprising the steps of:
receiving a biometric information sample from a biometric information source of the individual;
characterising the biometric information sample;
comparing the characterised biometric information sample against some of a plurality of stored templates to determine a registration profile comprising a predetermined number of indicators of a plurality of templates that most closely match the characterised biometric information sample;
comparing the registration profile against at least a stored registration profile to determine an identification associated with a registration profile similar to the determined registration profile; and,
identifying the individual when the associated registration profile is similar with the determined registration profile within a first predetermined limit.
The advantages of a system in accordance with this invention are numerous. For example, registration of authorized users requires less information from a user since information inherent to the database of templates is used to more accurately register biometric information and biometric data provided from an individual.